New load balancing webclient CRUD

Webclient  Use scenarios

Previously, I introduced   What is blocking 、 Non blocking , And the corresponding client library , Non blocking in

High concurrency

、

Out of memory

Under the circumstances , It's still a good choice , When the respondent's service response is slow 、 Or when you ask the other person , I don't really want to know the result returned by the other party , You can use  Webclient  To make non blocking requests . Next, we will talk about non blocking client Libraries  Webclient How to add, delete, modify and search .

Webclient  Of RestFul  request

One 、RESTful Style and HTTP method

be familiar with RESTful Style friends , You should know RESTful style API Use HTTP method Express operations on resources .

Let's talk about the usage of these resource scenarios .

POST

POST The following methods are commonly used ：

• block() Block the method to get the response result

• subscribe() Non blocking asynchronous result subscription method

• retrieve(） obtain HTTP Response body ,exchange() In addition to getting HTTP Response body , You can also get HTTP  Status code 、headers、cookies etc. HTTP Message information .

• Use Mono Receive the response result of a single object , Use Flux Receive the response result of the collection class object .

• Placeholder syntax parameter passing method

Submit data for simulation form

public void testFormSubmit() {

 MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
 map.add(&quot;username&quot;, &quot;damoin&quot;);
 map.add(&quot;UID&quot;, &quot;11024319902323&quot;);

 Mono<String> mono = webClientBuilder.build().post()
 .uri(&quot;http://rest-service-service/add&quot;)
 .contentType(MediaType.APPLICATION_FORM_URLENCODED)
 .body(BodyInserters.fromFormData(map))
 .retrieve()
 .bodyToMono(String.class);

 System.out.println(mono.block());
}


As shown above , When you submit the form , You need to specify the form data type , And the specific data of the form , We know ： Common form data is based on map The form , To get the response after the request, return , have access to

retrieve

function , At the same time, we can use Mono To type the returned result , If it is a single object, use Mono, If it's a collection stream , have access to Flux. meanwhile , If you want to block the information that returns the result , Can pass

block

Function to handle .

Transfer objects to JSON Send as data

public void testPostJson() {
 SysUser user = new SysUser();
 user.setRealName("dwdwdww");
 user.setPhone("32323232");
 Mono<String> mono = webClientBuilder.build()
 .post()
 .uri(&quot;http://rest-service-service/add&quot;)
 .contentType(MediaType.APPLICATION_JSON)
 .bodyValue(user)
 .retrieve()
 .bodyToMono(String.class);

 System.out.println(mono.block());
 }


Here, the transmitted data is displayed in Json Format to send to the other party , It is also necessary to indicate the data type

MediaType.APPLICATION_JSON

, Other functions are the same as above .

Simulate sending... To the server JSON String data

If sometimes the other person doesn't need one JSON object , Maybe you need a JSON character string , Then what shall I do? ？

public void testPostJsonStr() {
 String jsonStr = "{\"realName\": \"damon\",\"phone\": \"32323232\"}";
 Mono<String> mono = webClientBuilder.build().post()
 .uri(&quot;http://rest-service-service/add&quot;)
 .contentType(MediaType.APPLICATION_JSON)
 .body(BodyInserters.fromValue(jsonStr))
 .retrieve()
 .bodyToMono(String.class);

 //  Output results
 System.out.println(mono.block());
}


here , The data type is also  

MediaType.APPLICATION_JSON

, But the transmission is JSON strand .

DELETE

Use  DELETE Method to delete resources , Delete an existing resource , Use webClient Of delete() Method . This method will report to URL Send a message on behalf of the resource HTTP DELETE Method request ：

public void testDelete() {
 webClientBuilder.build()
 .delete()
 .uri("http://rest-service-service/1");
}


PUT

Modify an existing resource , Use webClient Of put() Method . This method will report to URL Send a message on behalf of the resource HTTP PUT Method request ：

public void testPut() {
 SysUser user = new SysUser();
 user.setRealName("dwdwdww");
 user.setPhone("32323232");

 Mono<String> mono = webClientBuilder.build()
 .put()
 .uri(&quot;http://rest-service-service/1&quot;)
 .contentType(MediaType.APPLICATION_JSON)
 .bodyValue(user).retrieve().bodyToMono(String.class);

 System.out.println(mono.block());
}


Here's a biography json Send and modify the data format , After modification, the modification result information will be returned .

GET

After adding data , Let's look at the data object , If it's an object data , have access to  Mono：

@GetMapping(value = "/getClientResByWebClient2", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
 public Mono<String> getClientResByWebClient2() throws Exception {
 Mono<String> resp = webClientBuilder.build()
 .get()
 .uri(&quot;http://diff-ns-service-service/all/getService&quot;)
 .retrieve().bodyToMono(String.class);
 //.exchange().flatMap(clientResp -> clientResp.bodyToMono(String.class));

 resp.subscribe(body -> System.out.println(body));
 return resp;
 }


If it's multiple objects , That's set set , You need to use Flux To get ：

public void testFlux() {
 Flux<SysUser> flux = webClientBuilder.build()
 .get()
 .uri(&quot;http://diff-ns-service-service/all&quot;)
 .retrieve()
 .bodyToFlux(SysUser.class);
 List<SysUser> li = flux.collectList().block();
 assert li != null;
 System.out.println(&quot;li Number of set elements ：&quot; + li.size());
}